1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 6721-11:2012Plastics Determination ofdynamic mechanical propertiesPart 11: Glass transition temperatureBS ISO 6721-11:2012 BRITISH STANDARDNational forewordThis British St
2、andard is the UK implementation of ISO 6721-11:2012. The UK participation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plastics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include
3、all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 65186 1 ICS 83.080.01 Compliance with a British Standard cannot confer immunity from legal obligations.This Bri
4、tish Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 6721-11:2012 ISO 2012Plastics Determination of dynamic mechanical propertiesPart 11: Glass transition temperaturePlast
5、iques Dtermination des proprits mcaniques dynamiques Partie 11: Temprature de transition vitreuseINTERNATIONAL STANDARDISO 6721-11First edition 2012-04-01Reference number ISO 6721-11:2012(E)BS ISO 6721-11:2012ISO 6721-11:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All
6、rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of
7、 the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 6721-11:2012ISO 6721-11:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federatio
8、n of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.
9、 International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance wit
10、h the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approva
11、l by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 6721-11 was prepared by Technical Committee
12、 ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties.ISO 6721 consists of the following parts, under the general title Plastics Determination of dynamic mechanical properties: Part 1: General principles Part 2: Torsion-pendulum method Part 3: Flexural vibration Resonance-curve method Part
13、4: Tensile vibration Non-resonance method Part 5: Flexural vibration Non-resonance method Part 6: Shear vibration Non-resonance method Part 7: Torsional vibration Non-resonance method Part 8: Longitudinal and shear vibration Wave-propagation method Part 9: Tensile vibration Sonic-pulse propagation m
14、ethod Part 10: Complex shear viscosity using a parallel-plate oscillatory rheometer Part 11: Glass transition temperature Part 12: Compressive vibration Non-resonance method ISO 2012 All rights reserved iiiBS ISO 6721-11:2012ISO 6721-11:2012(E)IntroductionThis part of ISO 6721 covers the use of dyna
15、mic mechanical analysis (DMA) procedures, in the temperature scanning mode, to determine a value for the glass transition temperature of plastics. It provides an alternative procedure to the use of differential scanning calorimetry (DSC) (see ISO 11357-2) for this measurement.DMA is used to determin
16、e the variation of the storage modulus, loss modulus and tan delta as a function of temperature and frequency. From these data, a value for the glass transition is determined. Many types of commercial equipment are available that use this technique and, in principle, it applies to all the loading mo
17、des described in ISO 6721-1.The procedures minimize errors due to thermal lag of the specimen, which varies with the heating rate used, through assuming the specimen temperature is given by the measured oven temperature1). This eliminates the need for the temperature of the specimen to be measured d
18、irectly by, for example, a thermocouple embedded in the specimen.1) See Sims G.D., Gnaniah S.J.P., Calibration Procedures for Increased Confidence in DMA Measurements, ICCM 11, Edinburgh, July 2009.iv ISO 2012 All rights reservedBS ISO 6721-11:2012Plastics Determination of dynamic mechanical propert
19、ies Part 11: Glass transition temperatureWARNING The use of this part of ISO 6721 may involve hazardous materials, operations and equipment. The document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user to establish appropriate heal
20、th and safety practices and to determine the applicability of regulatory limitations prior to its use.1 ScopeThis part of ISO 6721 specifies methods for determining a value of the glass transition temperature (Tg) from the dynamic mechanical properties measured during a linear temperature scan under
21、 heating conditions. The glass transition temperature is an indicator of the transition from a glassy state to a rubbery state.Usually referred to as dynamic mechanical analysis (DMA), the methods and their associated procedures can be applied to unreinforced and filled polymers, foams, rubbers, adh
22、esives and fibre-reinforced plastics/composites. Different modes (e.g. flexure, compression, tension) of dynamic mechanical analysis can be applied, as appropriate, to the form of the source material.NOTE For tests undertaken in the flexure or torsion mode, an additional procedure is included to ide
23、ntify the severity of the influences of thermal lag on the measured data (see Annex B).2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of
24、the referenced document (including any amendments) applies.ISO 6721-1:2011, Plastics Determination of dynamic mechanical properties Part 1: General principles3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 6721-1 and the following apply.3.1glass trans
25、ition temperatureTgtemperature of the point of inflection of the decrease in the storage modulus curve corresponding to the transition NOTE 1 This temperature often agrees with the temperature at the peak of the loss modulus data.NOTE 2 It is expressed in degrees Celsius (C).NOTE 3 See Figure 1, dat
26、a point 1.INTERNATIONAL STANDARD ISO 6721-11:2012(E) ISO 2012 All rights reserved 1BS ISO 6721-11:2012ISO 6721-11:2012(E)3.2temperature at onsetTonsettemperature corresponding to the onset of the transition from glassy state, as defined by the intercept of two tangents in the storage modulus curveNO
27、TE 1 The first tangent is extrapolated from a linear portion of the curve prior to the transition, and the second tangent is extrapolated from the point of inflection of the decrease in the curve corresponding to the glass-rubber transition .NOTE 2 It is expressed in degrees Celsius (C).NOTE 3 See F
28、igure 1, data point 5.3.3temperature at peak of loss modulus dataTlosstemperature of the peak of the loss modulus curveNOTE 1 It is expressed in degrees Celsius (C).NOTE 2 See Figure 1, data point 2.3.4temperature at peak of tan delta dataTtan deltatemperature of the peak in the tan delta curveNOTE
29、1 It is expressed in degrees Celsius (C).NOTE 2 See Figure 1, data point 3.3.5reference glass transition temperatureTg(0)value of the extrapolated temperature at 0 C/min heating rate that is used for specification and contract requirementsNOTE 1 It is expressed in degrees Celsius (C).NOTE 2 See Figu
30、re 2.3.6QA glass transition temperatureTg(n)value taken from the calibration curve at n C/min heating rate that is used for quality assurance purposes, by agreement, with heating rate dependent equipment (i.e. not the extrapolated Tg(0)valueNOTE 1 It is expressed in degrees Celsius (C).NOTE 2 See 9.
31、3.2. 4 PrincipleA specimen of known geometry is placed or held in a suitable mechanical loading system in an enclosed temperature chamber, or oven, that can be heated at a controlled rate. The specimen is mechanically oscillated at a fixed frequency, and changes in the viscoelastic response of the m
32、aterial are monitored and recorded as a function of the test temperature. The dynamic properties (storage modulus, loss modulus and tan delta) are determined from the load and displacement data recorded throughout the test (see ISO 6721-1). The glass transition temperature (Tg) is determined as the
33、point of inflection in the storage modulus vs. the temperature plot. The test procedure described minimizes errors due to the thermal lag, which varies with the heating rate used, of the specimen temperature through assuming the specimen temperature is given by the measured oven temperature. 2 ISO 2
34、012 All rights reservedBS ISO 6721-11:2012ISO 6721-11:2012(E)5 Equipment5.1 Dynamic mechanical analyserThe test equipment shall be capable of heating at rates from 1 C/min to 10 C/min over the required temperature range and mechanically oscillating the specimen at the reference frequency of 1 Hz. Th
35、e equipment should be capable of applying the temperature ramp profile to within 5 % of the required heating rate.The instrument shall continuously monitor and record the load applied to the specimen, and the corresponding displacement as a function of the measured temperature, in order to determine
36、 the storage modulus, loss modulus and tan delta. The load and displacement capabilities of the equipment shall be sufficient for the specimens tested.The equipment shall be calibrated, as required by the equipment user manual see Annex A.5.2 Devices for measuring test specimen dimensionsThese shall
37、 be in accordance with ISO 6721-1:2011, 5.6.6 Test specimen6.1 GeneralThe test specimen shall be in accordance with ISO 6721-1:2011, 6.1. 6.2 Shape and dimensionsThe dimensions of the specimen shall be as required by the equipment for the selected test mode.6.3 PreparationThe preparation of the test
38、 specimen shall be in accordance with ISO 6721-1:2011, 6.3. ISO 2012 All rights reserved 3BS ISO 6721-11:2012ISO 6721-11:2012(E)61732541000M M tan 2 5000500T180Key1 inflection point (storage modulus) (= Tg) T temperature, C2 peak (loss modulus) (= Tloss) M storage modulus, MPa3 peak (tan delta) (= T
39、tan delta) M loss modulus, MPa4 start point (storage modulus) tan tan delta5 onset (storage modulus)(= Tonset)6 endset (storage modulus)7 end point (storage modulus)Figure 1 Plot of dynamic mechanical data against temperature7 Number of specimensThis shall be in accordance with ISO 6721-1:2011, Clau
40、se 7.Prepare additional specimens (at least three) to assess the heating rate dependency of the method according to Clause 9.28 ConditioningThis shall be in accordance with ISO 6721-1:2011, Clause 8.4 ISO 2012 All rights reservedBS ISO 6721-11:2012ISO 6721-11:2012(E)9 Test procedure9.1 Test atmosphe
41、reThis shall be in accordance with ISO 6721:2011, 9.1NOTE Measurements can be undertaken under static air conditions or an inert atmosphere. However, it is important that the calibration and the specimen tests be performed under identical conditions.9.2 Assessment of heating rate dependence9.2.1 Hea
42、ting rate dependence ProcedureCalibrate the instrument in accordance with Annex A. Position the temperature sensor in the instrument as closely as possible to the sample under test, but ensuring it is not touching it. The position of the sensor shall remain undisturbed for subsequent specimen tests.
43、 If moved, recalibration may be necessary (see Annex A).Undertake tests according to Method A (see 9.3.1) to assess the heating rate dependence of the material/equipment.9.2.2 Heating rate dependence ResultsIf the temperature at the inflection points is shown to vary by more than 2 C between the dif
44、ferent heating rates, use Method A (see 9.3.1). NOTE For this case, a quality assurance procedure to reduce the testing time is also available (see 9.3.2).If the results are shown to vary by less than 2 C between the different heating rates, use Method B (see 9.3.3).9.3 Operation 9.3.1 Method A Rate
45、-dependent resultsMount the specimen into the instrument.Apply a constant rate temperature scan from at least 50 C below to 50 C above the transition region(s) of interest at heating rates of 3 C/min, 5 C/min and 10 C/min. Use a new specimen for each heating rate.The reference test frequency of 1 Hz
46、 shall be used.The load/displacement on the specimen shall be selected so that the specimen deformation is within the elastic range of the material being tested. The applied level shall remain constant to within 10 % of the initial value applied. Record the load and displacement data as a function o
47、f temperature, so that the storage modulus, loss modulus and tan delta can be calculated and plotted against temperature (see Figure 1). Determine the temperature at the inflection point for the storage modulus curve (see Figure 1, data point 1) at each heating rate.Plot the temperature of the infle
48、ction points as a function of heating rate, as shown in Figure 2. Extrapolate the data to meet the y-axis at 0 C/min using a linear fit. Report the extrapolated value to 0 C/min as Tg(0). These data form the “calibration curve” shown in Figure 2.NOTE The determination of the extrapolation value can
49、be aided by an additional scan at 1 C/min, but care is needed if the material state (e.g. degree of cure) changes during the scan. ISO 2012 All rights reserved 5BS ISO 6721-11:2012ISO 6721-11:2012(E)024 6810 12180200TnTg(0)Keyn heating rate, C/minT temperature, CTg(0)extrapolation to value at 0 C/min heating rate measured data at stated heating rateFigure 2 Determination of Tg(0)at 0 C/min from calibration curve9.3.2 Method QA Quality control testing R
